Thread: Rebuilt V8 - Very Rattly ValveTrain!

Originally Posted by I Love My Landy!

My Dad tried the 50 thou machined pedestals today. Should have made 80 thou more preload at the lifters. Noise was in fact worse apparently. Okay so maybe 80 thou is overkill, so tried 25 thou shims (a 40 thou increase in lifter preload). A tiny bit better, but still terrible. I think Dad was going to try 35 thou shims next (a 24 thou increase). I can't see that working, so next we are going to remove the inlet manifold and have a look at the lifters. Maybe try new lifters and even bolt on our old heads (which are still in great nick and we never had any problems with them. Probably just lap the valves in and get the stems machined the same). If that doesn't work, some petrol and a match should rid us of any more worries

Anybody got a good Isuzu 110 for sale?

Edward

G`day Edward ,

that`s not what i thought you were going to type .

Disregard the last in brackets , i missed the word More .

To me lifter noise is unique it sounds like nothing else . ( When you typed the bloke knew the noise from his office it wasn`t a surprise .)

It doesn`t sound like pushrods tapping on the head but if the pushrods have shiny marks up and down where they pass through the head .

Valve springs that coil bind don`t make the same noise but could be checked . Fitted length is around 40.40mm

As the valve stem height is lower than usual ( which means something like the seats are taller fitting valve head or the stem end has been ground if factory valves ) is there a chance the valve stem guides have been set at a height for 14 bolt heads which is 4mm taller than a ten bolt head which is 15mm still not the same noise .

If you look at the 14 bolt heads you have not fitted .

The head has a pad on each of the 4 corners to measure its thickness 2 short and 2 long

The measurement is from the head face/gasket surface to the flat surface on top of the pad .

The 10 bolt head and 14 bolt head have different thicknesses .

The measurements for 10 bolt heads on the vehicle ( using the heads not fitted to locate the pads ) .

A new 10 bolt 3.9 head that has not been skimmed will be ,

the short pair 22.94 mm

the tall pair 62.56 mm







( Following won`t explain the rattle but help me understand .You will understand your figures better than me and it`s most likely me not following .50 off the pedestal to give 80 ( 50 x 1.6 ) would mean the untouched pedestal would give zero .Adding the initial 25 i think it was to the untouched pedestal would give ( 25 x 1.6 ) 40 but woulds be a minus figure .The figure of 20 off the pedestal would give 32 preload
The figure of 40 off the pedestal would give 64 preload The figure of 50 off the pedestal would give 80 preload ( add the 25 shim gives 25 off for 40 preload )If the above makes sense do you still have the base 35-55 preload you initially mentioned should this be added . )

Originally Posted by PLR

G`day Edward ,

that`s not what i thought you were going to type .

Disregard the last in brackets , i missed the word More .

( Following won`t explain the rattle but help me understand .You will understand your figures better than me and it`s most likely me not following .50 off the pedestal to give 80 ( 50 x 1.6 ) would mean the untouched pedestal would give zero.

Correct.

Originally Posted by PLR

Adding the initial 25 i think it was to the untouched pedestal would give ( 25 x 1.6 ) 40 but woulds be a minus figure. The figure of 20 off the pedestal would give 32 preload
The figure of 40 off the pedestal would give 64 preload The figure of 50 off the pedestal would give 80 preload ( add the 25 shim gives 25 off for 40 preload)

Yep, that;s what i mean.

Originally Posted by PLR

If the above makes sense do you still have the base 35-55 preload you initially mentioned should this be added . )

My Dad measured the preload again today by putting marks on the pushrod before and after the rocker shafts are torqued down. I can't remember at what shim thinkness he found the most favourable results, but he did say that the preloads measured within spec but the noise continued.

We have been trying to fix this problem for a long while. Is there a chance we could have damaged the cam during this time? (We initially ran the cam in properly for over 20 min). All pushrods are still spinning.

Thanks again PLR,

Edward

Originally Posted by I Love My Landy!

Correct.

Yep, that;s what i mean.



My Dad measured the preload again today by putting marks on the pushrod before and after the rocker shafts are torqued down. I can't remember at what shim thinkness he found the most favourable results, but he did say that the preloads measured within spec but the noise continued.

We have been trying to fix this problem for a long while. Is there a chance we could have damaged the cam during this time? (We initially ran the cam in properly for over 20 min). All pushrods are still spinning.

Thanks again PLR,

Edward

I edited the post above you replied to i missed the more preload or the word more .

It seems if anything you have used more preload than required and when the figure should have been close it still rattled .

The thing is you and your Dad are looking/listening at it i`m only guessing or suggesting and don`t have the full picture and i don`t want to direct you off track .


If the push rods are spinning the taper of the cam lobes and the convex shape of the lifter base are still there and this is what gets lost .

So on the fact the pushrods are spinning i would suggest the cam should be ok .

From what you have typed i would consider the lifters themselves but i would not expect more that one or two and so my apprehension of this suggestion .

I don`t think new/unused lifter failure is common as may be suggested at times .

Originally Posted by PLR

G`day Edward ,

To me lifter noise is unique it sounds like nothing else . ( When you typed the bloke knew the noise from his office it wasn`t a surprise .)

It doesn`t sound like pushrods tapping on the head but if the pushrods have shiny marks up and down where they pass through the head .

Valve springs that coil bind don`t make the same noise but could be checked . Fitted length is around 40.40mm

As the valve stem height is lower than usual ( which means something like the seats are taller fitting valve head or the stem end has been ground if factory valves ) is there a chance the valve stem guides have been set at a height for 14 bolt heads which is 4mm taller than a ten bolt head which is 15mm still not the same noise .

If you look at the 14 bolt heads you have not fitted .

The head has a pad on each of the 4 corners to measure its thickness 2 short and 2 long

The measurement is from the head face/gasket surface to the flat surface on top of the pad .

The 10 bolt head and 14 bolt head have different thicknesses .

The measurements for 10 bolt heads on the vehicle ( using the heads not fitted to locate the pads ) .

A new 10 bolt 3.9 head that has not been skimmed will be ,

the short pair 22.94 mm

the tall pair 62.56 mm

This section of your previous post was not showing for me earlier. Thank you for all those measurements. We'll get to work double checking everything. When we saw the rebuild 3.9 heads we noticed that the valve faces sat further into the combustion chamber (i.e. they looked thicker). We purchased the heads already reconditioned, so we don't know exactly what valves were used.

We are not sure if the noise if purely lifters or not. You could describe it as a harsh 'white noise' if that makes any sense. Perhaps that's what happens when most of the lifters are tapping. I took a video of it the other day. I might see if i can upload it to YouTube or something.

This whole process has been frustrating, especially since we have a fast approaching deadline to meet, but at least we are learning a bit along the way. I do look forward to reporting our solution though!

Thanks again,

Edward

From all of the above,, I think a sound file would help everyone this end..

Originally Posted by Pedro_The_Swift

From all of the above,, I think a sound file would help everyone this end..

I'll see if i can get something sorted.

Edward

Engine Noise Diagnosis-Part 1 - YouTube


Minute 17 . 58 and 13 .10

This is what a lifter rattle can sound like but is a big gap .

Electronic noise for me is not clear .

If i find better i`ll tell .

PM replied

Had another listen

The 13 .10 when he`s pulling the leads i can make out the clicking noise .

The clicking noise is the lifter type noise

G`day Edward ,

after reading through your replies , etc .

I think you`ve found it .

Had a look in one of the books as said .

For 10 bolt 3.9 ltr head

The fitted distance between the stem guide/seal and retaining cap is 0.450/11.4mm

A camshaft with the std lift of 0.390in/9.9mm has a clearance .060/1.5mm between the valve stem seal/guide and valve spring retainer cap at full lift .

You typed a difference in height of the valves at 0.110/2.794mm . ( difference between your 10 and 14 bolt heads .)

If the valve stem guides are fitted to factory height for a 3.9 head in the 3.9 heads on the vehicle .

This would give a .050/1.27mm defict or lack of clearance . ( if fitted to 14 bolt spec add .158/4.0132mm )

This would make a noise that no amount of preload adjustment would alter .

This could bend pushrods because of coming up solid .

Of coarse this is only a theory but is the most plausible one that my mind keeps coming to if not coil binding .

i now don`t think the lifters are at fault at all but again theory .


Cheers



Bit more from book.

1.575 in fitted spring height .

1.095 in spring cold bind height .

Minimum clearance between coils 0.050 in .